1. Field of the Invention
The invention relates to a method for securing the data traffic between a mobile radio network and an IMS network as well as a corresponding data network.
2. Description of the Related Art
The IMS subnetwork (IMS=IP-based Multimedia Subsystem) standardized in the 3GPP organization (3GPP=3rd Generation Partnership Project) provides a mobile subscriber in a mobile radio network with multimedia services. To achieve an authenticated logon of a mobile subscriber in an IMS network, the IMS-AKA protocol (AKA=Authentification and Key Agreement) is known from the related art (see “Access security for IP-based services (Release 5)”, 3GPP SA3 (Security) (2002-09), Technical specification 33.203 v5.3.0). A security architecture is used in IMS release 5, in which security architecture key material is contained in a so-called ISIM (IP Multimedia Services Identity Module) on the chip card of the mobile terminal of the subscriber, with this key material further being stored in computers in the IMS network. It is thus disadvantageous here that a mechanism has to be provided by which identical key material is stored in the network and on the ISIM.